Question
Physics Question on Current electricity
Potentiometer measures the potential difference more accurately than a voltmeter because
A
it has a wire of high resistance
B
it has a wire of low resistance
C
it does not draw current from external circuit
D
it draws a heavy current from external circuit
Answer
it does not draw current from external circuit
Explanation
Solution
When we measure the emf of a cell by the potentiometer then no current flows in the circuit in zero-deflection condition ie, cell is in open circuit. Thus, in this condition the actual value of a cell is found. In this way, potentiometer is equivaient to an ideal voitmeter of infinite resistance.